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6.4 Electrophotographic Process
Roberto Medeiros
The electrophotographic process consists of seven stages (see Figure 6.4). For the purpose of this text,
we will be describing the process using a negatively charged dry toner. The process is the same for a
positive toner except the polarity would be reversed in each stage.
Figure 6.4 Electrophotographic Imaging System
Charging
In the first stage, a high negative voltage of approximately -900 volts is provided to a charge roller (see
Figure 6.5). The voltage used varies by manufacturer and model. The charge roller applies a uniform
layer of negative charge to the surface of the drum. The resistivity of the unexposed photosensitive drum
coating allows the charge to remain on the surface.
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